Prescribed fires are a powerful tool for reducing fire hazards by decreasing amounts of fuel. The main objective is to analyze the effects of prescribed burning on the understory vegetation composition as well as on the soil characteristics of a reforested stand of
Historically, fire has played a dominant role in shaping many forest plant communities [
Fire regimes have changed as a consequence of human activities and large wildland fires are now more likely to occur. Changing socioenvironmental conditions, such as abandonment of traditional agricultural crops, abandonment of pastoralism, or decreasing exploitation of timber resources, are leading to higher fuel loads and consequently to the increase in the frequency and severity of wildfires [
The most recent studies on the effects of prescribed fire in Europe are related to shrublands [
Regarding soil properties, prescribed burning has been shown to increase pH and nutrient availability immediately following fire and through the first year [
Canarian forest stands have been subjected to long-term degradation, especially since the European colonization of the islands [
Little is known about historic fire regimes in the Canary Islands, which makes it difficult to determine which conditions and frequency of burning would be the most appropriate to restore vegetation as well as prevent large wildfires. In the past, wildfire were infrequent but large in extension [
If fire management is based on a misunderstanding of plant life history or incorrect historical perceptions, burning could have potentially large effects on forest community diversity [
Management of pine forest in Mediterranean countries usually involves cutting the shrub understory to break fuel continuity within the canopy [
The objective of this study was to analyze the effects of clearing and prescribed fire treatments on the understory community and soil parameters by testing the following main hypotheses: (1) cutting and burning will have different effects on species composition, and different species will be identified as descriptors of each treatment; (2) burning will modify soil parameters more intensively than just cutting, but some of these parameters such as pH or exchangeable cations will recover to pretreatment values in less than two years.
The study was conducted at the pine forest of Artenara, in Gran Canaria, Canary Islands, Spain (UTM-X 436449, UTM-Y 3099622), which is part of the Protected Landscape of Las Cumbres, under environmental protection by the Canarian Network of Natural Protected Areas [
The study site was divided into six plots of between 1.5 and 2 ha each, depending on topographical complexity, where experimental treatments (3 cut and 3 burnt) were applied, and three control plots of approximately 0.5–1 ha each. Control plots were smaller than treated plots to meet management objectives in the largest possible area. From several weeks to a month before burning, the woody understory vegetation of all plots and the lowest branches of the pines were cleared, with the help of chainsaws, except in the controls, as in usual practice to break the vertical continuous fuel ladder before burning. Dead fuel was kept on the ground. This practice allows a homogeneous burning and maintains flame heights of less than 1.5 m due to the spreading of the dead fuel along the surface covering fuel gaps [
Three 100 m2 square subplots per treatment plot and one per control plot were located at random. Environmental variables such as rock and litter cover percentage were visually estimated per subplot. Altitude, aspect, and slope were also measured per subplot. All the species in the subplots were listed and their percentage cover was visually estimated and noted on a scale of 1 to 9 (1: trace; 2: <1%; 3: 1-2%; 4: 2–5%; 5: 5–10%; 6: 10–25%; 7: 25–50%; 8: 50–75%; 9: >75%) [
Four samples of the top 10 cm soil (only organic horizon) were taken per subplot and pooled to obtain a single composite sample before analysis. Soil samples were analyzed following the common standard methods for organic carbon (Walkey-Black method), available phosphorus (Olsen method), potassium, magnesium, calcium, and sodium (Bower method) [
Vegetation and soil sampling were carried out before treatment (spring 2005) and six (winter 2006), twelve (spring 2007; only vegetation), eighteen (winter 2007), and twenty-four (spring 2008) months after burning.
To ensure that there were no significant differences in understory species composition, richness, and diversity before burning and cutting treatment, a distance based permutational MANOVA [
In order to test our hypothesis of species composition changes after management practices, distance based permutational-repeated measures MANOVA was fitted, with treatment (control, burnt, and cut) and period (four repeated measures: six, twelve, eighteen, and twenty-four months after treatment) used as fixed factors and the plots as a paired factor. The analyses were based on Bray-Curtis distances of the cover data of understory vascular species. Same procedure was applied to species richness and diversity data but based on Euclidian distances. Significant terms were investigated using a posteriori pairwise comparisons with the PERMANOVA
We performed a similarity percentage (SIMPER) routine [
Finally, to test our second hypothesis we performed one-way distance based permutational ANOVA [
The absence of significant differences in species composition (Pseudo-
We found a total of 107 species belonging to 39 families (12 species were only identified at genus level) and 44% of the species were common to the different treatment areas (Table
Cutting and burning effects on vegetation in
Species composition | Species richness | Species diversity | ||||
---|---|---|---|---|---|---|
PERMANOVA | Pseudo- |
|
Pseudo- |
|
Pseudo- |
|
|
||||||
Treatment | 4.78 | 0.00 | 2.80 | 0.07 | 7.73 | 0.00 |
Sampling period | 1.59 | 0.02 | 1.38 | 0.24 | 0.34 | 0.91 |
Treatment * sampling period | 0.68 | 0.85 | 0.27 | 0.95 | 0.42 | 0.88 |
|
||||||
Pairwise |
|
|
|
|
|
|
|
||||||
Control-burnt | 2.39 | 0.00 | — | — | 2.15 | 0.04 |
Control-cut | 2.08 | 0.00 | — | — | 2.10 | 0.04 |
Cut-burnt | 2.09 | 0.00 | — | — | 4.50 | 0.00 |
Principal component analysis ordination diagram showing species and samples according to treatment. Species that play consistent roles (SIMPER; mean dissimilarity to SD ratio higher than 1) in determining the dissimilarity between treatments (Table
Regarding descriptive species responsible for the similarity within treatments, presented using the results from the SIMPER procedure (Table
Cutting and burning effects on species composition in
Species | Av. Abund. | Av. Sim. | Sim./SD | Contrib. % | Cum. % |
---|---|---|---|---|---|
Control (average similarity 54.59) | |||||
|
6.25 | 14.25 | 2.55 | 26.11 | 26.11 |
|
2.67 | 6.52 | 3.33 | 11.94 | 38.05 |
|
2.75 | 4.74 | 1.36 | 8.69 | 46.74 |
|
2.08 | 4.55 | 2.09 | 8.33 | 55.07 |
|
1.83 | 4.53 | 4.67 | 8.31 | 63.38 |
|
2.42 | 4.30 | 1.36 | 7.89 | 71.26 |
|
2.08 | 2.70 | 0.82 | 4.94 | 76.20 |
|
1.33 | 2.46 | 0.97 | 4.50 | 80.70 |
|
1.25 | 1.38 | 0.64 | 2.53 | 83.23 |
|
1.00 | 1.27 | 0.79 | 2.33 | 85.56 |
|
1.17 | 1.23 | 0.53 | 2.26 | 87.82 |
|
1.00 | 1.16 | 0.53 | 2.13 | 89.94 |
|
1.08 | 0.96 | 0.31 | 1.75 | 91.70 |
|
|||||
Cut (average similarity 26.30) | |||||
|
1.64 | 5.12 | 0.74 | 19.48 | 19.48 |
|
1.53 | 4.77 | 0.76 | 18.13 | 37.61 |
|
1.42 | 3.95 | 0.68 | 15.01 | 52.63 |
|
0.61 | 1.84 | 0.21 | 7.00 | 59.63 |
|
1.22 | 1.23 | 0.45 | 4.68 | 64.31 |
|
0.89 | 0.98 | 0.41 | 3.72 | 68.03 |
|
0.83 | 0.92 | 0.44 | 3.49 | 71.52 |
|
0.92 | 0.81 | 0.42 | 3.08 | 74.60 |
|
0.69 | 0.75 | 0.38 | 2.86 | 77.46 |
|
1.00 | 0.66 | 0.39 | 2.52 | 79.98 |
|
0.69 | 0.62 | 0.34 | 2.35 | 82.33 |
|
0.67 | 0.52 | 0.33 | 1.98 | 84.31 |
|
0.69 | 0.44 | 0.16 | 1.66 | 85.97 |
|
0.64 | 0.42 | 0.30 | 1.59 | 87.56 |
|
0.75 | 0.40 | 0.30 | 1.54 | 89.09 |
|
0.36 | 0.36 | 0.17 | 1.37 | 90.46 |
|
|||||
Burnt (average similarity 37.33) | |||||
|
2.11 | 7.20 | 2.39 | 19.27 | 19.27 |
|
2.00 | 6.16 | 1.61 | 16.49 | 35.76 |
|
1.56 | 2.84 | 0.71 | 7.61 | 43.37 |
|
1.58 | 2.79 | 0.70 | 7.48 | 50.85 |
|
1.25 | 2.65 | 0.98 | 7.09 | 57.94 |
|
1.39 | 2.33 | 0.82 | 6.23 | 64.17 |
|
1.42 | 2.10 | 0.67 | 5.63 | 69.81 |
|
0.92 | 1.30 | 0.54 | 3.49 | 73.30 |
|
0.78 | 0.83 | 0.44 | 2.24 | 75.53 |
|
0.86 | 0.80 | 0.38 | 2.15 | 77.69 |
|
0.94 | 0.78 | 0.30 | 2.10 | 79.79 |
|
0.69 | 0.65 | 0.37 | 1.75 | 81.53 |
|
0.78 | 0.65 | 0.41 | 1.75 | 83.28 |
|
0.75 | 0.60 | 0.39 | 1.62 | 84.90 |
|
1.39 | 0.57 | 0.28 | 1.54 | 86.43 |
|
0.64 | 0.49 | 0.34 | 1.30 | 87.73 |
|
0.67 | 0.48 | 0.33 | 1.29 | 89.02 |
|
0.56 | 0.43 | 0.34 | 1.16 | 90.18 |
The absence of significant differences for any of the soil variables prior to treatment (Table
Cutting and burning effects on soil in
Prefire | 6 months | 18 months | 24 months | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
C | CT | B | C | CT | B | C | CT | B | C | CT | B | |
pH | 6.27 (0.15) | 6.29 (0.20) | 6.46 (0.18) | 6.5 (0.15)a | 6.18 (0.24)b | 6.74 (0.23)a | 6.2 (0.75) | 6.28 (0.37) | 6.52 (0.32) | 6.47 (0.50) | 6.44 (0.24) | 6.51 (0.31) |
% OM | 3.47 (0.25) | 4.04 (0.67) | 3.95 (0.72) | 5.03 (2.03) | 5.28 (1.42) | 4.98 (1.89) | 3.87 (1.06) | 4.26 (0.82) | 4.03 (0.74) | 4.27 (0.96) | 4.5 (0.60) | 4.08 (1.01) |
ppm P | 12.67 (4.62) | 11.56 (5.73) | 12.75 (5.75) | 10.67 (3.06)a | 8.89 (7.75)a | 21.11 (8.25)b | 14 (5.29)ab | 10 (5.39)a | 19.78 (7.97)b | 6.67 (4.16) | 7.56 (7.73) | 12.67 (7.42) |
Ca | 9.33 (1.70) | 8.58 (1.50) | 9.75 (1.48) | 9.53 (2.37)ab | 8.82 (1.87)a | 11.82 (1.94)b | 11.13 (3.79) | 9.31 (2.08) | 12.02 (3.70) | 11 (3.89) | 9.38 (1.78) | 10.76 (3.24) |
Mg | 5.53 (1.70) | 4.47 (1.50) | 4.83 (1.48) | 4.47 (2.37) | 4.09 (1.87) | 4.18 (1.94) | 5.53 (3.79) | 4.47 (2.08) | 5 (3.70) | 6.47 (3.89) | 4.82 (1.78) | 4.84 (3.24) |
K | 1.37 (1.70) | 1.29 (1.50) | 1.3 (1.48) | 2.3 (2.37)a | 1.64 (1.87)b | 1.7 (1.94)b | 1.9 (3.79) | 1.5 (2.08) | 1.56 (3.70) | 2.00 (3.89) | 1.47 (1.78) | 1.43 (3.24) |
Na | 0.87 (0.15) | 0.91 (0.20) | 0.93 (0.18) | 1.37 (0.15) | 1.21 (0.24) | 1.32 (0.23) | 2.5 (0.75) | 2.18 (0.37) | 2.12 (0.32) | 1.83 (0.50) | 1.51 (0.24) | 1.4 (0.31) |
C: control; CT: cut; B: burnt; different letters indicate significant differences (permutational ANOVA, 9999 permutations,
Plant species (107 spp.) recorded during the research of the cutting and burning effects on vegetation composition in
Family | Species | Abbrev. | Orig. | C | CT | B |
---|---|---|---|---|---|---|
Alliaceae |
|
All_sp. | x | x | ||
Apiaceae |
|
Fer_lin | ES | x | x | x |
Apiaceae |
|
Tod_mon | EG | x | x | x |
Apiaceae |
|
Tor_nod | x | x | ||
Asteraceae |
|
And_pin | ES | x | x | x |
Asteraceae |
|
Arg_ada | ES | x | x | x |
Asteraceae |
|
Art_thu | ES | x | x | x |
Asteraceae |
|
Cal_arv | MN | x | x | |
Asteraceae |
|
Car_pyc | MN | x | x | x |
Asteraceae |
|
Car_ten | MN | x | ||
Asteraceae |
|
Cen_asp | MN | x | x | x |
Asteraceae |
|
Con_sp. | SI | x | ||
Asteraceae |
|
Gal_tom | MN | x | x | x |
Asteraceae |
|
Hed_rha | MN | x | ||
Asteraceae |
|
Hyp_gla | MN | x | x | x |
Asteraceae |
|
Lac_ser | MN | x | x | |
Asteraceae |
|
Leo_tar | PI | x | ||
Asteraceae |
|
Per_web | ES | x | x | x |
Asteraceae |
|
Rei_tin | PN | x | x | |
Asteraceae |
|
Sen_ten | SN | x | ||
Asteraceae |
|
Son_aca | ES | x | x | x |
Asteraceae |
|
Son_asp | MN | x | x | x |
Asteraceae |
|
Son_ole | MN | x | x | x |
Asteraceae |
|
Son_sp. | x | x | x | |
Asteraceae |
|
Tol_bar | MN | x | x | |
Asteraceae |
|
Tra_por | MN | x | ||
Asteraceae |
|
Uro_pic | PN | x | ||
Boraginaceae |
|
Ech_ono | ES | x | x | x |
Boraginaceae |
|
Myo_sp. | x | x | x | |
Brassicaceae |
|
Ery_bic | SN | x | x | x |
Brassicaceae |
|
Hir_inc | MN | x | x | x |
Brassicaceae |
|
Rap_rap | SN | x | x | |
Brassicaceae |
|
Sis_off | MN | x | ||
Campanulaceae |
|
Leg_hyb | MN | x | x | x |
Campanulaceae |
|
Wah_lob | SN | x | ||
Caryophyllaceae |
|
Pin_rad | SI | x | x | |
Caryophyllaceae |
|
Sil_gal | MN | x | x | |
Caryophyllaceae |
|
Sil_vul | MN | x | x | x |
Caryophyllaceae |
|
Ste_med | PI | x | x | x |
Caryophyllaceae |
|
Pet_nan | x | |||
Caryophyllaceae |
|
Cer_glo | MN | x | x | x |
Chenopodiaceae |
|
Che_sp. | x | |||
Crassulaceae |
|
Aeo_per | ES | x | x | x |
Crassulaceae |
|
Aeo_sim | ES | x | x | |
Crassulaceae |
|
Gre_aur | EG | x | x | |
Crassulaceae |
|
Umb_gad | PN | x | x | x |
Dipsacaceae |
|
Pte_dum | ES | x | x | |
Ericaceae |
|
Eri_arb | SN | x | ||
Fabaceae |
|
Ade_fol | ES | x | ||
Fabaceae |
|
Cha_pro | ES | x | x | x |
Fabaceae |
|
Lat_ann | PI | x | x | x |
Fabaceae |
|
Tel_mic | ES | x | x | x |
Fabaceae |
|
Tri_arv | PN | x | x | |
Fabaceae |
|
Tri_cam | PN | x | x | x |
Fabaceae |
|
Tri_sca | PN | x | x | x |
Fabaceae |
|
Tri_sp. | x | x | x | |
Fabaceae |
|
Vic_dis | PN | x | x | x |
Fabaceae |
|
Vic_lut | MN | x | x | x |
Fabaceae |
|
Vic_sat | MN | x | x | |
Fabaceae |
|
Vic_sp. | x | x | x | |
Fumariaceae |
|
Fum_sp. | x | x | x | |
Geraniaceae |
|
Ero_cic | MN | x | x | |
Geraniaceae |
|
Ero_sp. | x | x | x | |
Geraniaceae |
|
Ger_dis | MN | x | ||
Geraniaceae |
|
Ger_mol | MN | x | x | |
Geraniaceae |
|
Ger_pur | MN | x | x | |
Geraniaceae |
|
Ger_rot | MN | x | x | |
Geraniaceae |
|
Ger_sp. | x | x | x | |
Hypericaceae |
|
Hyp_ref | ES | x | ||
Hypolepidaceae |
|
Pte_aqu | PN | x | ||
Iridaceae |
|
Rom_col | SN | x | x | |
Lamiaceae |
|
Lam_amp | SI | x | x | |
Lamiaceae |
|
Mic_ben | ES | x | x | x |
Lamiaceae |
|
Sal_can | ES | x | x | x |
Lamiaceae |
|
Sta_arv | MN | x | x | |
Orchidaceae |
|
Neo_mac | PN | x | x | x |
Oxalidaceae |
|
Oxa_pes | II | x | ||
Papaveraceae |
|
Pap_rho | II | x | x | x |
Pinaceae |
|
Pin_can | ES | x | x | x |
Pinaceae |
|
Pin_hal | SI | x | ||
Pinaceae |
|
Pol_tet | MN | x | ||
Poaceae |
|
Air_car | MN | x | x | |
Poaceae |
|
Ani_mad | MN | x | ||
Poaceae |
|
Ani_rig | MN | x | ||
Poaceae |
|
Ave_bar | MN | x | x | |
Poaceae |
|
Ave_fat | SN | x | ||
Poaceae |
|
Bri_max | MN | x | x | |
Poaceae |
|
Cyn_ech | MN | x | ||
Poaceae |
|
Lam_aur | PN | x | ||
Poaceae |
|
Vul_gen | MN | x | x | |
Polygonaceae |
|
Rum_buc | SN | x | x | x |
Polygonaceae |
|
Rum_lun | ES | x | ||
Primulaceae | A |
Ast_lin | PN | x | x | x |
Ranunculaceae |
|
Ran_cor | SN | x | x | x |
Resedaceae |
|
Res_lut | PN | x | ||
Rubiaceae |
|
Gal_apa | MN | x | x | x |
Rubiaceae |
|
Gal_par | PN | x | x | x |
Rubiaceae |
|
She_arv | MN | x | x | |
Rubiaceae |
|
Gal_mur | PN | x | ||
Rubiaceae |
|
Gal_sp. | x | |||
Rubiaceae |
|
Gal_ver | MN | x | ||
Scrophulariaceae |
|
Mis_oro | PN | x | ||
Scrophulariaceae |
|
Ver_hed | MN | x | x | |
Solanaceae |
|
Sol_nig | MN | x | x | |
Urticaceae |
|
For_ang | ES | x | ||
Urticaceae |
|
Urt_sp. | x | |||
Valerianaceae |
|
Cen_cal | MN | x | x | x |
Cutting and burning effects on species composition in
Species | Control | Cut | Av. Diss. | Diss./SD | Contrib. % | Cum. % |
Av. Abund. | Av. Abund. | |||||
|
||||||
|
6.25 | 1.64 | 8.95 | 1.61 | 12.37 | 12.37 |
|
2.75 | 0.89 | 4.00 | 1.34 | 5.53 | 17.90 |
|
2.67 | 1.22 | 3.76 | 1.20 | 5.20 | 23.10 |
|
2.42 | 1.00 | 3.72 | 1.35 | 5.14 | 28.24 |
|
2.08 | 0.92 | 3.30 | 1.10 | 4.56 | 32.80 |
|
1.83 | 0.69 | 2.55 | 1.37 | 3.52 | 36.33 |
|
1.08 | 0.22 | 2.44 | 0.71 | 3.38 | 39.71 |
|
0.67 | 0.72 | 2.43 | 0.56 | 3.36 | 43.07 |
|
0.17 | 1.42 | 2.38 | 1.14 | 3.28 | 46.35 |
|
1.33 | 0.83 | 2.10 | 1.02 | 2.91 | 49.26 |
|
1.25 | 0.06 | 2.10 | 1.02 | 2.90 | 52.16 |
|
1.17 | 0.06 | 2.06 | 0.91 | 2.85 | 55.01 |
|
2.08 | 1.53 | 1.94 | 0.87 | 2.69 | 57.69 |
|
1.00 | 0.75 | 1.92 | 1.01 | 2.66 | 60.35 |
|
1.00 | 0.67 | 1.74 | 1.13 | 2.40 | 62.76 |
|
0.83 | 0.64 | 1.62 | 0.94 | 2.25 | 65.00 |
|
0.75 | 0.36 | 1.56 | 0.75 | 2.15 | 67.15 |
|
0.75 | 0.56 | 1.48 | 0.91 | 2.05 | 69.20 |
|
0.33 | 0.61 | 1.45 | 0.71 | 2.01 | 71.21 |
|
0.33 | 0.69 | 1.22 | 0.96 | 1.69 | 72.90 |
|
0.67 | 0.11 | 1.18 | 0.77 | 1.63 | 74.53 |
|
0.67 | 0.19 | 1.17 | 0.73 | 1.61 | 76.14 |
|
0.00 | 0.69 | 1.14 | 0.45 | 1.58 | 77.73 |
A |
0.50 | 0.31 | 1.09 | 0.76 | 1.51 | 79.24 |
|
0.58 | 0.14 | 1.04 | 0.81 | 1.44 | 80.68 |
|
0.33 | 0.36 | 1.01 | 0.57 | 1.40 | 82.08 |
|
0.25 | 0.56 | 0.94 | 0.63 | 1.30 | 83.38 |
|
0.25 | 0.39 | 0.89 | 0.60 | 1.23 | 84.60 |
|
0.08 | 0.47 | 0.70 | 0.59 | 0.97 | 85.57 |
|
0.33 | 0.19 | 0.69 | 0.60 | 0.96 | 86.53 |
|
0.25 | 0.28 | 0.67 | 0.56 | 0.92 | 87.45 |
|
0.42 | 0.00 | 0.66 | 0.53 | 0.91 | 88.37 |
|
0.33 | 0.08 | 0.64 | 0.47 | 0.89 | 89.26 |
|
0.17 | 0.19 | 0.63 | 0.44 | 0.87 | 90.13 |
|
||||||
Species | Control | Burnt | Av. Diss. | Diss./SD | Contrib. % | Cum. % |
Av. Abund. | Av. Abund. | |||||
|
||||||
|
6.25 | 2.11 | 6.75 | 1.75 | 10.98 | 10.98 |
|
2.08 | 0.94 | 3.08 | 1.17 | 5.01 | 15.99 |
|
2.75 | 1.56 | 3.01 | 1.26 | 4.90 | 20.89 |
|
2.42 | 1.42 | 2.73 | 1.27 | 4.44 | 25.33 |
|
2.67 | 1.58 | 2.43 | 1.12 | 3.95 | 29.28 |
|
0.75 | 1.39 | 2.18 | 0.88 | 3.55 | 32.83 |
|
0.67 | 0.86 | 2.09 | 0.71 | 3.40 | 36.23 |
|
1.08 | 0.33 | 2.09 | 0.71 | 3.40 | 39.62 |
|
1.17 | 0.69 | 1.99 | 0.95 | 3.23 | 42.85 |
|
1.25 | 0.50 | 1.83 | 1.06 | 2.97 | 45.83 |
|
1.33 | 0.78 | 1.77 | 1.11 | 2.87 | 48.70 |
|
1.00 | 1.39 | 1.74 | 1.16 | 2.83 | 51.53 |
|
1.00 | 0.75 | 1.56 | 0.95 | 2.54 | 54.07 |
|
0.75 | 0.78 | 1.41 | 0.98 | 2.29 | 56.36 |
|
0.83 | 0.56 | 1.39 | 0.98 | 2.25 | 58.62 |
|
0.33 | 0.92 | 1.37 | 1.07 | 2.23 | 60.85 |
|
1.83 | 1.25 | 1.31 | 0.93 | 2.12 | 62.97 |
|
0.33 | 0.69 | 1.22 | 0.78 | 1.98 | 64.95 |
|
0.58 | 0.64 | 1.22 | 0.99 | 1.98 | 66.93 |
|
2.08 | 2.00 | 1.18 | 0.80 | 1.92 | 68.85 |
|
0.67 | 0.44 | 1.18 | 0.79 | 1.92 | 70.76 |
|
0.33 | 0.67 | 1.07 | 0.76 | 1.75 | 72.51 |
|
0.67 | 0.03 | 1.00 | 0.76 | 1.63 | 74.14 |
|
0.08 | 0.72 | 0.95 | 0.71 | 1.55 | 75.69 |
|
0.33 | 0.44 | 0.95 | 0.64 | 1.55 | 77.24 |
|
0.17 | 0.44 | 0.84 | 0.55 | 1.36 | 78.60 |
|
0.50 | 0.06 | 0.83 | 0.67 | 1.36 | 79.96 |
|
0.00 | 0.53 | 0.81 | 0.59 | 1.31 | 81.27 |
|
0.25 | 0.42 | 0.73 | 0.66 | 1.18 | 82.45 |
|
0.42 | 0.22 | 0.72 | 0.63 | 1.17 | 83.62 |
|
0.25 | 0.19 | 0.62 | 0.55 | 1.01 | 84.64 |
|
0.17 | 0.33 | 0.58 | 0.51 | 0.94 | 85.58 |
|
0.25 | 0.22 | 0.56 | 0.51 | 0.90 | 86.48 |
|
0.33 | 0.11 | 0.55 | 0.57 | 0.89 | 87.37 |
|
0.08 | 0.36 | 0.54 | 0.55 | 0.88 | 88.25 |
|
0.00 | 0.39 | 0.48 | 0.56 | 0.77 | 89.02 |
|
0.00 | 0.31 | 0.47 | 0.33 | 0.77 | 89.79 |
|
0.00 | 0.39 | 0.47 | 0.50 | 0.76 | 90.55 |
|
||||||
Species | Cut | Burnt | Av. Diss. | Diss./SD | Contrib. % | Cum. % |
Av. Abund. | Av. Abund. | |||||
|
||||||
|
1.22 | 1.58 | 3.41 | 0.97 | 4.73 | 4.73 |
|
0.89 | 1.56 | 3.18 | 0.87 | 4.41 | 9.14 |
|
1.00 | 1.42 | 2.96 | 1.00 | 4.10 | 13.25 |
|
1.42 | 0.44 | 2.88 | 0.91 | 4.00 | 17.25 |
|
0.92 | 0.94 | 2.70 | 0.76 | 3.75 | 21.00 |
|
0.67 | 1.39 | 2.70 | 1.00 | 3.75 | 24.75 |
|
0.72 | 0.86 | 2.55 | 0.76 | 3.54 | 28.28 |
|
0.36 | 1.39 | 2.49 | 0.74 | 3.45 | 31.73 |
|
0.69 | 1.25 | 2.47 | 1.03 | 3.43 | 35.16 |
|
1.53 | 2.00 | 2.47 | 0.76 | 3.43 | 38.59 |
|
1.64 | 2.11 | 2.36 | 0.77 | 3.27 | 41.86 |
|
0.69 | 0.92 | 2.13 | 0.90 | 2.95 | 44.82 |
|
0.61 | 0.44 | 1.97 | 0.64 | 2.74 | 47.55 |
|
0.83 | 0.78 | 1.95 | 0.89 | 2.70 | 50.26 |
|
0.75 | 0.75 | 1.73 | 0.88 | 2.40 | 52.66 |
|
0.56 | 0.78 | 1.67 | 0.87 | 2.32 | 54.98 |
|
0.36 | 0.69 | 1.55 | 0.75 | 2.16 | 57.14 |
|
0.64 | 0.56 | 1.55 | 0.81 | 2.15 | 59.28 |
|
0.47 | 0.72 | 1.50 | 0.74 | 2.09 | 61.37 |
|
0.69 | 0.00 | 1.40 | 0.42 | 1.94 | 63.31 |
|
0.06 | 0.69 | 1.37 | 0.46 | 1.90 | 65.21 |
|
0.22 | 0.53 | 1.37 | 0.58 | 1.89 | 67.11 |
|
0.14 | 0.64 | 1.20 | 0.66 | 1.67 | 68.78 |
|
0.08 | 0.67 | 1.19 | 0.63 | 1.65 | 70.43 |
|
0.19 | 0.39 | 1.04 | 0.54 | 1.44 | 71.87 |
|
0.28 | 0.42 | 0.98 | 0.56 | 1.36 | 73.23 |
|
0.39 | 0.19 | 0.97 | 0.56 | 1.35 | 74.58 |
|
0.56 | 0.22 | 0.92 | 0.59 | 1.28 | 75.86 |
|
0.19 | 0.44 | 0.90 | 0.56 | 1.25 | 77.11 |
|
0.22 | 0.33 | 0.89 | 0.46 | 1.23 | 78.34 |
|
0.06 | 0.50 | 0.84 | 0.60 | 1.16 | 79.50 |
|
0.11 | 0.39 | 0.78 | 0.53 | 1.08 | 80.57 |
|
0.08 | 0.36 | 0.76 | 0.47 | 1.06 | 81.63 |
|
0.36 | 0.22 | 0.68 | 0.55 | 0.94 | 82.57 |
|
0.25 | 0.36 | 0.67 | 0.57 | 0.93 | 83.50 |
|
0.00 | 0.31 | 0.67 | 0.32 | 0.92 | 84.42 |
|
0.06 | 0.33 | 0.63 | 0.41 | 0.87 | 85.29 |
|
0.22 | 0.00 | 0.54 | 0.33 | 0.75 | 86.04 |
A |
0.31 | 0.06 | 0.53 | 0.44 | 0.74 | 86.79 |
|
0.17 | 0.03 | 0.49 | 0.39 | 0.68 | 87.47 |
|
0.14 | 0.22 | 0.49 | 0.41 | 0.68 | 88.15 |
|
0.19 | 0.00 | 0.48 | 0.32 | 0.66 | 88.81 |
|
0.06 | 0.28 | 0.44 | 0.38 | 0.61 | 89.42 |
|
0.00 | 0.17 | 0.37 | 0.28 | 0.52 | 89.94 |
|
0.06 | 0.14 | 0.36 | 0.31 | 0.50 | 90.44 |
We only detected significant influence of the treatment on some soil parameters six and eighteen months after treatment. Six months after treatment, mean pH values were significantly different between treatments (Pseudo-
Prescribed fire is a useful management tool for preventing large wildfires [
Contrary to species richness, the abundance of understory plants is more sensitive to management [
Legume shrubs typical of the understory of the pine forest, such as
Species composition has changed due to management, and two years after the treatment differences remain (Table
As established in our first hypothesis, both treatments revealed different effects on species composition. Some authors found that, in high-density pine stands, minimal disturbances, such as surface fires, have a low impact on understory composition and production [
The impact of prescribed fire on soil nutrients is known to be more evident during the first year after fire, increasing the levels of the most important elements (P, N, K, and Ca), while in general after one year, soil nutrient content is more similar between burned and nonburned plots [
As hypothesized, fire modified soil parameters more intensively than just cutting, and treatment effects on soil variables lasted less than two years. Burning effects on soil nutrient can differ in direction and intensity from those caused by clearing treatments [
Increases in P and exchangeable cations in the surface soil after a low-intensity prescribed fire have been found as common [
Based on the obtained results, from an ecological point of view, prescribed fire appears to be a better management practice than simply cutting the woody understory. On the one hand, although none of the management practices resulted in pernicious effects on soil nutrient content, prescribed burning seems to favour a short-term pulse in soil nutrients. On the other hand, two years after treatments fuel reduction aims are accomplished, since dominant shrub species (
It should be noted that the stimulation of
Perhaps being an efficient and cheap method of forest fuel removal and fire hazard reduction [
The authors declare that there is no conflict of interests regarding the publication of this paper.
The authors thank Consejería de Medio Ambiente y Emergencias (Gran Canaria Council), especially UOFF and PRESA, for granting permission to work in